R Factor For Attic Rafter Insulation

Easiest insulation for layperson to install fairly inexpensive r value doesn t fluctuate as with loose fill.

R factor for attic rafter insulation.

The thicker the insulation the greater the r value. Owens corning raft r mate attic rafter vents. According to home advisor insulating your attic can cost between 1700 to 2100. The main factors that impact the cost are.

R value for fiberglass or wool batts per inch is between r3 and r3 5 pros. An insulation value of r 38 is at the high end and requires a minimum thickness of 12 inches. Add insulation to attic. Square footage of your attic.

The rafters in cathedral ceilings are usually made of 2x10 ft. If the joists are 10 inches deep the cavity can take high density r 30 insulation which is 8 1 2 inches thick more than enough for floor insulation. R 30c and r 38c are available in both kraft faced and unfaced. Type and material of your insulation.

Recommended insulation levels for retrofitting existing wood framed buildings. Find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces. If insulation is allowed to bunch against the inside slope of the roof between the rafters air will be blocked before it can traverse the attic. Rolls are usually used for long expanses such as length of floor for entire attic while batts are fit between studs in attic rafters.

Raft r mate attic rafter vents create a space between each rafter for air to flow freely up the rafters and into the attic. If the garage is open to the rafters the boards that support the roof use r 38 insulation between the rafters at the roof if they are 10 inches deep. Inspecting your attic insulation. Fiberglass r 19 batt insulation is about 6 inches thick and is available in 15 inch widths making it the correct size for insulating a two by eight floor joist system.

Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. Your attic should have a certain amount of insulation in it and the recommended level of insulation for your attic is dependent on where you live. Contractor or insulation installer s fee. First things first you need to go up into your attic inspect the condition of the insulation and calculate the current level of insulation.